I've never understood why online music is commodity priced. iTunes' buck-a-track model vastly overprices a lot of rotten music and arguably underprices the really good or popular tracks. Music alterna-store Amie Street, which alpha launched in 2006 and recently relaunched a more finished version, has a market-driven model, which also has the side effect of making it more likely that up-and-coming artists can find success in a very crowded market.
On Amie Street, all new music starts out as free: you can download new tracks at no cost, with no rights management encumbrances. But here's the thing: when people start to download a track, the price starts to go up. The more people buy it, the more it costs, up to a dollar a track. Furthermore, Amie Street users who recommend undiscovered tracks get a cut of sales for the tracks they recommend that sell well.
It's a head-slapper, wish-I-had-thought-of-it economic model, the kind of thing you'd expect to come out of a business school competition or from a bunch of college students (the founders are indeed in college). But will it work in the real world? I found a decent selection of indie music in most categories, and I mostly agreed with the recommendations of the Amie Street community, as reflected in the prices of songs. On this music service, you do get what you pay for.
See also: Sellaband, another interesting music model. This operation helps young music groups get recorded and also pays out for their success to the community. However, on Sellaband, you have to pony up a few bucks to earn a piece of the action.
If you want to stick with established artists, use a music discovery service such as Musicovery that indexes studio tracks.